In recent years, thin film transistor liquid crystal displays (TFT-LCDs) have been more and more widely used. In the meantime, the technology for thin film transistors to drive and control pixels has accordingly obtained development, and has developed from previous amorphous silicon thin film transistors to current low temperature poly-silicon thin film transistors, oxide thin film transistors, and so on.
Oxide thin film transistors have better characteristics, such as electron mobility, on-state current, switching characteristic and so on, than amorphous thin film transistors. Because of better uniformity, oxide thin film transistors have advantages in the number of masks and manufacturing difficulties, have less difficulties in manufacturing large-sized display devices, and are enough for an application for which a fast response and a larger current are required. Therefore, oxide thin film transistors are increasingly getting attention.
FIG. 1 is a schematic configuration drawing of the conventional oxide thin film transistor, and as illustrated, the current oxide thin film transistor comprises a substrate 1, a gate electrode 2, a gate insulating layer 3, a semiconductor layer 4, an etching stopping layer 5 and source/drain electrodes 7. In manufacturing an oxide thin film transistor, generally on the substrate 1, the processes of film-forming, exposing, developing, and etching are successively performed for a gate metal layer, a gate insulating layer, a metal oxide semiconductor layer, an etching stopping layer and a data line metal layer, so as to successively form the gate electrode 2, the gate insulating layer 3, the semiconductor layer 4, the etching stopping layer 5, and the source/drain electrodes 7.
The etching stopping layer 5 is usually of a multilayer film structure that is formed of one or more of silicon oxide (SiOx), silicon nitride (SiNx) and silicon oxynitride (SiON), thus has poor water resistance property and is prone to be penetrated by water vapor from the air in the subsequent manufacturing process of the product and in use, then making the semiconductor layer in the channel region below the etching stopping layer be subjected to damage and causing the product failure.